1. Field of the Invention.
The invention relates generally to blow-out preventers for use in closing well bore casement and, more particularly, but not by way of limitation, it relates to an improved blow out preventer for use during work over situations wherein submersible pump cables or other members are suspended in the well bore.
2. Description of the Prior Art.
The prior art includes a great number of blow-out preventer devices that are suitable for completely closing the well bore during an emergency situation, such hole closure devices utilize various mechanisms including hybrid form packers, gate valves and other plugging devices in effecting the reliable and tight hole closure. U.S. Pat. No. 2,746,709 in the name of Minor is but one prior teaching wherein a contractible rubber packer is actuated to seal off the annulus between a casing and an axially aligned tubing string. In the absence of tubing, the device is also effective to contract to a completely closed position thereby sealing off the casing extremities therebelow.